Flexible printed circuit forming contact surface around stator of rotary switch

ABSTRACT

A switch having movable contacts which make and break connections with conductive areas of a printed circuit. The printed circuit is on a flexible film base, wrapped around a cylindrical stator having a plurality of longitudinally movable contacts. The contacts are positioned by a rotary cam. The switch may have one or a plurality of axially aligned sections. Circuit elements, as resistors, capacitors, inductors, transistors or the like may be mounted directly on the film base.

United States Patent 3,683,132 Richardson Au 8, 1972 [54] FLEXIBLEPRINTED CIRCUIT 2,203,224 6/1940 Kimball ..200/153 LB FORMING CONTACTSURFACE 3,476,901 7/1969 Werda ..200/166 PC AROUND STATOR OF ROTARY3,531,603 9/1970 Asaman ..200/1 1 D SWITCH 3,562,464 2/1971 Vollum eta1. ..200/l66 PC Inventor: Lonnie J. Richardson, g L 3,567,894 3/1971Spreitzek ..200/166 PC [73] Assignee: Oak Electro/Netics Corp. PrimaryExaminer-J. V. Truhe Assistant Examiner-George A. Montanye l 70 [22]Flled Sept 9 Attorney-Hofgren, Wegner, Allen, Stellman and Mc- [21]Appl. No.: 70,203 Cord and Daniel C. McEachran 52 u.s. CI. .....200/11R, 200/153 LB, 200/166 PC, [571 ABSTRACT 200/168 K A switch havingmovable contacts which make and [51 Int. Cl. ..HOIh 19/62 breakconnections with conductive areas of a primed held of Search "200/166circuit. The printed circuit is on a flexible film base, 200/168 H I] H6 6 C wrapped around a cylindrical stator having a plurality oflongitudinally movable contacts. The contacts are [56] References cuedpositioned by a rotary cam. The switch may have one UNITED STATESPATENTS or a plurality of axially aligned sections. Circuit elements, asresistors, capacitors, inductors, transistors or ggo fil g the like maybe mounted directly on the film base. ange et a 3,177,306 4/1965 Mastney..200/1l D 17 Claims, 16 Drawing Figures PATENTEDM B 8 I972 3.683.132

sum 1 or 5 INVENTOR ATTORNEYS PATENIEDws 8 m2 3. 683. l 3 2 sum 3 nr 5FLEXIBLE PRINTED CIRCUIT FORMING CONTACT SURFACE AROUND STATOR OF ROTARYSWITCH DESCRIPTION OF THE PRIOR ART Various proposals have been made forcombining multi-position rotary switches with printed circuitry. See,for example, US. Pats. Nos. Luhn 2,794,081, Hartz 2,869,033 andVolkenburg 3,242,270. In general, the approach has been to use printedcircuit panels as the stator sections for multi-section rotary switches.This has some economies in material and labor, when compared with wiringa conventional rotary switch into a circuit, but does not represent acompact combination of switch and conduit.

SUMMARY OF THE INVENTION The present invention is concerned with a novelswitch construction utilizing printed circuitry on a flexible film,mounted on an elongated cylindrical switch stator with movable switchcontacts which make and break circuits with the conductive areas printedon the film. More particularly, the switch may have one or moresections, each section having a plurality of Iongitudinally movablecontacts actuated by a rotary cam.

One important feature of the present invention is that it provides aswitch mechanism which is inexpensive, compact and can be adapted foruse in any of a wide variety of different printed circuits. Therotor-stator structure of the switch can receive and operate movablecontacts in any or all of many separate positions for making andbreaking connections with a particular printed circuit.

Another feature of the present switch is its ability to readilyaccommodate additional gangs of movable contacts.

Still another feature resides in the flexible printed circuit which iswrapped around the cylindrical stator and has an exposed outer surfaceon which circuit elements, such as resistors, capacitors, inductors,transistors or the like, may be directly mounted.

Other features and objects will be apparent from the drawings and thedescription of the preferred embodimerit.

While an illustrative embodiment of the invention is shown in thedrawings, and will be described in detail herein, the invention issusceptible of embodiment in many different forms and it should beunderstood that the present disclosure is to be considered as anexemplification of the principles of the invention and is not intendedto limit the invention to the embodiment illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a switchembodying the invention;

FIG. 2 is a side view, as in FIG. 1, showing only the FIG. 6 is asection through an integral plastic insulating member fonning a portionof the stator and generally taken along line 6--6 of FIG. 5;

FIG. 7 is a fragmentary section showing a switch contact assembly as inFIG. 3, but in a different position;

FIG. 8 is an exploded view of the contact assembly;

FIG. 9 is a plan view of the cam for moving switch contact assemblies;

FIG. 10 is a side view of the cam in FIG. 9;

FIG. 1 l is a perspective view of another cam;

FIG. 12 is a plan view of a representative printed circuit sheet used inthe switch;

FIG. 13 is an enlarged fragmentary longitudinal section through asnaplock;

FIG. 14 is an enlarged fragmentary longitudinal section through alocating pin and receiver;

FIG. 15 is an end view from the left of FIG. 1; and

FIG. 16 is a section through a film clamping ring in open position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, apreferred form of the printed circuit switch of this invention includesa cylindrical stator 30 having an indexing mechanism 32 mounted at oneend thereof via an adaptor plate 36 and a rotor having a control orcircuit selector knob 34. Adaptor plate 36 is secured to the end ofstator 30 by screws 38 (FIG. 3) and the indexing mechanism 32 is in turnattached to the adaptor plate 36 by two screws 40 which extend intoreceivers 40a in the front end of stator 30.

As best seen in FIGS. 2 and 3, stator 30 includes three nonconductivemolded plastic sections, i.e., a front section 30a, a middle section3012, and a rear section 300. The cap or end stator sections 30a and 30care closed by flat end walls to prevent entry of dust into the switchassembly. The three sections 30a, 30b and 300 are held together bysuitable releasable or snap lock means which will be described below.

Each of sections 30a and 30b includes a circular array of contactassemblies 42 with each contact assembly 42 mounted in a slot-likereceiver 44 (FIGS. 2, 5 and 6) for longitudinal or axial slidingmovement between two spaced positions. Contact assemblies 42 can beomitted from some of the receivers 44 within an array whenever anincomplete array is needed to accommodate a desired switching function.The electrically conductive contacts of assemblies 42 are accessible atthe surface of stator 30 with the assemblies in either position. Thus,the illustrated embodiment is a ganged unit having two circular arraysof movable contact assemblies.

As shown in FIGS. 1, 3 and 5, a flexible printed circuit sheet 46 isprovided as a wrap-around on the outer surface of stator 30 forengagement with contact assemblies 42. The inner surface of the sheet 46includes a conductive printed circuit on a non-conductive substrate andis held against the outer surface of stator 30 by a series of threecircular clamp members 48. Preferably, one of the clamp members 48 ispositioned over or adjacent each circular array of sliding contactassemblies 42 to assure more positive contact of the printed circuitwith the contact assemblies.

In general, the device is used to switch between a variety of differentcontacts on the printed circuit by rotating knob 34 through a pluralityof different stations. A detentm'echanism holds the rotor in each statorand a different disposition of the various contact assemblies 42 withrespect to the printed circuit can be provided for each station ofselector knob 34.

Turning now to more specific details of construction of the device shownin FIG. 1, and with special reference to FIGS. 3 through 5, the selectorknob 34 is secured by a suitable set screw to a shaft 50 which has adouble-D configuration and extends through a continuous central axialbore in the indexing mechanism 32, the adaptor plate 36 and the stator30.

The indexing mechanism 32 (FIGS. 3 and 4) is similar to that shown byLewandowski et al. in US. Pat. No. 3,293,382, issued Dec. 20, 1966,employing a toothed detent wheel 52 on the shaft 50 with 12 radiallyextending spaced teeth 54 engaged by detent balls 46 mounted in ballreceivers 58 and urged inwardly between pairs of adjacent teeth 54 byleaf springs 60 to hold the rotor in each of twelve stations.

In stator 30, two axially spaced metal discs or cam plates 62 and 64 aremounted on shaft 50 for rotation therewith. The cam plates .62 and 64are received in deep recesses 66 in the distal ends of the bodies ofstator sections 30a and 30b and are axially slidable on shaft 50 forease of assembly.

The slot-like receivers 44 (FIGS. 2, and 6) are formed in the walls ofrecesses 66 of stator sections 30a and 30b and the side walls ofreceivers 44 have inwardly projecting guide flanges 70 for slidablyreceiving and retaining the contact assemblies 42. As seen in FIGS. 3, 7and 8, each contact assembly 42 includes an electrically insulatingcontact retainer 74 and an open V-shaped electrically conductive leafspring contact 76 having contact points 78 at each end protrudingslightly above the outer surface of stator 30 in engagement with theprinted circuit sheet 46. Each contact retainer.74 is provided with agroove 80 on each side thereof which slidably receives an inwardlyprojecting flange 70 of the receiver 44. The slot-like receivers 44extend to and are open at the lip of the side wall of the recess 66 insections 30a and 30b so that the holders 74 can be readily mounted intoselected receivers 44 from their open ends prior to joining the statorsection.

As best seen in FIGS. 7 and 9 through 11, the cam plates 62 and 64 haverises or lift surfaces 62a and 64a, and falls 62b and 64b therebetween,coincident with various detented indexed positions. The lift surfaces62a and 64a are for the purpose of slidably driving the contactassemblies 42 in receivers 44 from right to left as viewed in FIGS. 1-3and 7 as a cam rise 62a or 64a is presented to each contact assembly 42on rotation of shaft 50. The falls similarly permit return of assemblies42 from left to right.

Referring to FIGS. 3 and 6, each of stator sections 30b and 300 has ahub 84 at the proximal end thereof through which the central cylindricalbore for shaft 50 extends. A hold down leaf spring 90 (see also FIG. 5)having a plurality of 12 radially extending leaf spring arms 90a isreceived and held against rotation by lug portions 90b in radial grooves86 of each hub 84. A tubular spacer member 93 extends between each hub84 and the facing cam plate 62 or 64 to keep the cam plates properlyseated in recesses 66.

As seen in FIGS. 3, 7 and 8, each contact retainer 74 has a raisedsurface portion 74a for riding on and against a cam plate 62 or 64. Theother end of each contact retainer 74 abuts a leaf spring arm a and eacharm 90a has sufficient bias to retain end 74a against the lows or fallsof cam plate 62 or 64. As the cam plate is rotated with shaft 50 from aposition in FIG. 3 in which a low is presented to end 74a of a contactretainer 74 to a position in FIG. 7 in which a high is presented, thecontact retainer 74 is driven to the left against the urging of leafspring 90 relative to printed circuit sheet 46 carrying the contactpoints 78 to a new position on the printed circuit sheet. It will beapparent that different cam arrangements on the cam plates can be toproduce a variety of different results with regard to moving respectiveones of the contact assemblies 44 to new positions relative to printedcircuit sheet 46, to produce a variety of different making and breakingeffects on a given printed circuit.

Although the device described in the drawings uses only two gangs ofcircularly arranged contacts, many more gangs can be used by adding moresections 30b between the sections 30a and 300 with each section 30bprovided with a cam plate of similar or different cam arrangement. Theprinted circuit of sheet 46 would be commensurately extended in lengthto accommodate the added contact assemblies 42. As additional sections30b are added, the length of shaft 50 will, of course, need to beextended to accommodate the extra length of the stator 30.

For snaplocking the stator sections together, referring to FIGS. 5, 13and 14, at the proximal end of each of the bodies of sections 30b and300 are provided two snaplock receivers 98 which receive snaplock lugs96 on the distal ends of each of the bodies of sections 300 and 30b. Thetwo snaplock receivers 98 on each of sections 30b and 300 are spacedapproximately 120 from each other about the axis of shaft 50, as are thelugs 96 on sections 30a and 30b. And a locating pin 100 on the distalend of each of sections 30a and 30b is received in a bore in theproximal end of the adjacent sections 30b and 30c, pin 100 being spacedfrom each of the lock lugs 96 on the respective statorv section. Thelocating pin 100 locates the adjacent sections in proper angulardispositions with respect to each other and the snap lugs 96 arereceived in the receivers 98 and resiliently held therein to releasablysecure the adjacent sections together. It will also be seen that a longarray of sections 30b, including contact assemblies 42,

cam plates and springs 90, can be joined in this manner to each otherbetween sections 30a and 300.

After the three sections 30a, 30b and 300 have been joined to form thestator 30 containing the operating elements described above, and theindexing mechanism 30 and knob 34 are assembled, the printed circuitsheet 46 can be wrapped around the stator and the clamps 48 applied toproduce the device as it appears in F IG. 1.

The printed circuit sheet 46, best seen in FIG. 12, includes anon-conductive, flexible plastic substrate portion 104 and a circuitprinted of conductive material such as copper at 106. In the form shown,the conductive circuit 106 includes two stations for each electricalcontact 76 used, e.g., one for the make position of each contact 76 andone for the break position or different make position of each contact76. Lead portions backed by non-conductive substrate 104 extend from ofcircumferentially unevenly each of the two separate circuits from thetwo gangs of the switch shown in FIG. I as seen at 108 in FIGS. 12 and15 so that the switch can be properly electrically connected with otherelectrical circuitry.

Spaced around the exterior of the assembled rotor sections, as best seenin FIG. 2, are three circular arrays spaced, radially projectinglocating pins 110 which receive the flexible printed circuit by impalingapproximately spaced holes 112 in the sheet 46 much in the same manneras a film is threaded on sprockets of a movie projector.

One clamp 48 is applied over each circular array of projections or pins110. As shown in FIGS. 15 and 16 each clamp 48 is generally circular inconfiguration and has a weakened or hinge portion 116 for opening andclosing the clamp. To lock the clamp in closed position, a snapprojection 118 is provided at one end which can be received and held bya snap receiver 120 when the clamp is closed around the stator sectionand printed circuit sheet 46. The inner surface of each clamp 48 has acircular array of receivers 172, properly spaced for receiving acircular array of locating pins 1 10.

In the preferred form, as best seen in the plan view of the printedcircuit board as shown in FIG. 12, the spacing holes 112 are provided atdifferent distances from each other from left to right, to correspondwith the uneven circumferential spacing of projections or pins 110 onthe outer surface of stator 30 so that the printed circuit sheet 46 canbe wrapped around the assembly of stator sections from only one startingplace and in only one direction, thereby assuring proper alignment ofthe printed circuit with the contact points 78 to achieve the desiredswitching effect.

In operation, the knob 34, shaft 50 and cam plates 62 and 64 are rotatedone or more stations and held or detented in the selected station by theindex mechanism. Rotation of each cam plate causes one of its rises orfalls to act against each contact assembly 42 of the respective gang,moving it longitudinally and causing the contact to move to or through anew electrical contact position on the printed circuit, e.g., to make orbreak or make-and-break a circuit, depending on the design of theprinted circuit. Since there can be several lift surfaces or rises, aswell as falls, on a single cam plate, several contact assemblies in eachgang can be moved simultaneously. The design of the cam plate can bevaried to give a dwell period for a contact or a faster or slower risetime to allow one contact to make or break before another. Variations inthe height or thickness of contact pads on the printed circuit,different rise levels of the cam plate, and varied lift surfaces of thecam plate can allow an almost infinite variety of switching functionsdepending on the diameter of the switch and the number of detentpositions. Thus the switch can be adapted to receive any of a widevariety of printed circuit sheets, providing any of an unlimited numberof switching function possibilities.

The printed circuit may be a single layer with copper on one or bothsides, or may be a multilayer circuit sheet. The choice depends on thecomplexity of the circuit and the switching functions to be performed.Interconnections of a multilayer circuit sheet may be by conventionalmeans, e.g. eyelets, plating thru holes, etc. Circuit elements such asresistors, capacitors, inductors, transistors and the like can besecured directly on the outer exposed surface of the circuit sheet andelectrically connected to the switch circuitry at such eyelets. The leadportion of the switch circuit may be brought out from the end of theswitch or from the side for connection into an overall circuit. Forimproved life and minimal contact resistance, the printed circuit ispreferably plated.

I claim:

1. A printed circuit switch comprising an insulating cylindrical statorand a rotor mounted in the stator for rotary movement, a flexibleprinted circuit sheet wrapped around and secured to the outer surface ofsaid stator and having electrically conductive paths thereon, andelectrical contact means mounted for movement responsive to rotation ofsaid rotor, with said contact means being movable relative to theprinted circuit sheet for contacting said conductive paths.

2. The switch of claim 1 wherein said contact means includes a pluralityof electrical contacts and said printed circuit comprises a separateconductive portion at each of two stations for each contact of saidplurality of contacts.

3. The switch of claim 1 wherein said electric contact means is mountedfor movement between two stations.

4. The switch of claim 1 including mounting means for the electricalcontact means in said stator mounting the contact means for slidingmovement in a path generally parallel to the axis of the rotor.

5. The switch of claim 4 wherein said contact means comprises aplurality of separate contacts and said rotor includes cam means mountedon a rotary shaft for moving each electric contact on rotation of theshaft.

6. The switch of claim 5 wherein said contact means comprises a circulararray of a plurality of contacts each mounted in a separate contactretainer member with each retainer member separately longitudinallyslidable in said mounting means.

7. The switch of claim 6 wherein said slidable retainer members areequally spaced in the circular array around the axis of the stator.

8. The switch of claim 1 further characterized in that said electricalcontact means includes contact holder means supporting electricalcontact elements, said electrical contact elements being in engagementwith the inner surface of said flexible sheet and said rotor comprises ashaft coaxial with said cylindrical stator and cam means mounted formovement with the shaft for moving said contact holder means.

9. The switch of claim 8 including spring means biasing said contactholder means toward said cam means.

10. The switch of claim 1 wherein the stator comprises a plurality oflongitudinally stacked stator sections each having contact means, saidcontact means having a circular array of longitudinally slidablecontacts in electrical contact with the printed circuit and each arrayof contacts has separate cam means for driving the contacts in onedirection and separate spring means for returning the contacts in theother direction.

11. The switch of claim 1 including locator holes in said sheet receivedon radially projecting pins on the outer surface of the stator forproperly locating the conductive paths relative to the contact means.

12. The switch of claim 11 including a clamp means receiving andcooperating with said radially projecting for locking said gangedsections together.

16. The switch of claim 15 including locator pin means properly locatingsaid snaplock means and stator sections relative to each other inpreselected disposition.

17. The switch of claim 1 including means for properly locating theprinted circuit sheet on the stator outer surface.

1. A printed circuit switch comprising an insulating cylindrical statorand a rotor mounted in the stator for rotary movement, a flexibleprinted circuit sheet wrapped around and secured to the outer surface ofsaid stator and having electrically conductive paths thereon, andelectrical contact means mounted for movement responsive to rotation ofsaid rotor, with said contact means being movable relative to theprinted circuit sheet for contacting said conductive paths.
 2. Theswitch of claim 1 wherein said contact means includes a plurality ofelectrical contacts and said printed circuit comprises a separateconductive portion at each of two stations for each contact of saidplurality of contacts.
 3. The switch of claim 1 wherein said electriccontact means is mounted for movement between two stations.
 4. Theswitch of claim 1 including mounting means for the electrical contactmeans in said stator mounting the contact means for sliding movement ina path generally parallel to the axis of the rotor.
 5. The switch ofclaim 4 wherein said contact means comprises a plurality of separatecontacts and said rotor includes cam means mounted on a rotary shaft formoving each electric contact on rotation of the shaft.
 6. The switch ofclaim 5 wherein said contact means comprises a circular array of aplurality of contacts each mounted in a separate contact retainer memberwith each retainer member separately longitudinally slidable in saidmounting means.
 7. The switch of Claim 6 wherein said slidable retainermembers are equally spaced in the circular array around the axis of thestator.
 8. The switch of claim 1 further characterized in that saidelectrical contact means includes contact holder means supportingelectrical contact elements, said electrical contact elements being inengagement with the inner surface of said flexible sheet and said rotorcomprises a shaft coaxial with said cylindrical stator and cam meansmounted for movement with the shaft for moving said contact holdermeans.
 9. The switch of claim 8 including spring means biasing saidcontact holder means toward said cam means.
 10. The switch of claim 1wherein the stator comprises a plurality of longitudinally stackedstator sections each having contact means, said contact means having acircular array of longitudinally slidable contacts in electrical contactwith the printed circuit and each array of contacts has separate cammeans for driving the contacts in one direction and separate springmeans for returning the contacts in the other direction.
 11. The switchof claim 1 including locator holes in said sheet received on radiallyprojecting pins on the outer surface of the stator for properly locatingthe conductive paths relative to the contact means.
 12. The switch ofclaim 11 including a clamp means receiving and cooperating with saidradially projecting pins to secure said sheet to the stator outersurface and in contact with the electrical contact means.
 13. The switchof claim 1 wherein said stator comprises a plurality of longitudinallystacked and ganged stator sections, each having contact means attachedthereto.
 14. The switch of claim 13 wherein said rotor includes aplurality of cams, one for cooperating with each of said contact means.15. The switch of claim 13 including snaplock means for locking saidganged sections together.
 16. The switch of claim 15 including locatorpin means properly locating said snaplock means and stator sectionsrelative to each other in preselected disposition.
 17. The switch ofclaim 1 including means for properly locating the printed circuit sheeton the stator outer surface.